IRC would have been the best tool if it did session logging instead of requiring the use of bouncers. IRC is text-only, nonproprietary and completely distraction-free.
But you don’t have to use IRC. There are more modern federated protocols like Matrix and XMPP that do session logging. There are quite a lot of FOSS communities on them that are very active.
However, the main complaint here isn’t about Discord vs other chat protocols. It’s about the use of Discord as a community support forum. Unlike forums like Discourse, Discord messages aren’t searchable on the web. If a person asks a question on it and gets a solution, it’s then lost forever. Another person with the same question has to ask again. It completely defeats the utility of FOSS - of reusing someone else’s solutions.